1. Field of the Invention
The present invention relates to a vehicle equipped with an automatic clutch disengagement/engagement system that automatically disengages and engages a friction clutch coupling between an engine and a transmission.
2. Description of the Related Art
A vehicle equipped with an automatic clutch disengagement/engagement system that automatically disengages and engages a friction clutch coupling between an engine and a transmission is known in the art. In connection with the automatic clutch disengagement and engagement system, the present assignee, for example, have filed several applications in USPTO such as U.S. patent application Ser. Nos. 09/150,686 on Sep. 10, 1998, 09/207,180 on Dec. 8, 1998, and 09/426,837 on Oct. 26, 1999. The entire disclosures thereof are incorporated herein by reference. In addition, the present assignee also proposed a vehicle that is further equipped with an automatic brake system (Hill Start Aid System) in Japanese Patent Application Laid Open Publication No. 11-236931 published on Aug. 31, 1999, the entire disclosure of which is incorporated herein by reference. This is referred to as "first preceding invention" in this specification. With the hill start aid system, it is possible to maintain a braking force even after a driver's foot leaves a brake pedal. This is particularly advantageous when the vehicle is on an uphill. A driver's operation is simplified when he or she attempts to restart the vehicle on the hill. The driver can manipulate a manual switch or lever located in a passenger compartment to arbitrarily adjust a timing of brake release (brake releasing point). In this automatic brake system, the brake is designed to be released when a clutch stroke reaches a predetermined value. Therefore, the driver actually adjusts and determines this clutch stroke value.
However, it is impossible to release the brake at the optimum timing for both on a flat road condition and on a slope condition. Specifically, if the brake release point is determined to match a flat road condition, the brake is released too early when the vehicle is on a slope. Conversely, if the brake release point conforms to the on slope condition, then the brake release takes place too late when the vehicle is restarted on the flat road.
Therefore, the driver must readjust the brake release point to experience optimum brake releasing on both the flat and non-flat road. However, this is troublesome. In addition, the optimum brake release point varies depending upon inclination of the road, load on the vehicle, etc. Therefore, finding out the optimum brake release point is sometimes difficult for the driver by manual readjustment. It is also troublesome for the driver if he/she is frequently required to readjust the brake release point in order to experience the same level of comfortableness in starting under any condition regardless of inclination of the road, load on the vehicle, etc.